Changes in the glycosylation pattern of circulating gonadotropins after acute administration of gonadotropin-releasing hormone in patients with anorexia nervosa.
To study the involvement of gonadotropin-releasing hormone (GnRH) in glycosylation of circulating gonadotropin isoforms in anorexia nervosa (AN), 14 amenorrhoic patients with AN, 14 age-matched volunteers in early follicular phase, and five normal-weight re-fed patients with AN were investigated under baseline conditions and after acute administration of GnRH. Plasma gonadotropins were assayed using IRMA before and after concanavalin A affinity chromatography. Baseline plasma gonadotropin levels were lower for both AN and re-fed AN patients than in controls (P<0.005). The increase in FSH and LH after GnRH administration was lower than in controls for AN (P<0.005) and re-fed AN (P<0.005 and P<0.05 respectively) patients. Percentages of total gonadotropin not bound to concanavalin A (complex carbohydrate chains) under baseline conditions were higher in patients with AN than in controls (P<0.005) but decreased after GnRH administration (P<0.001). In re-fed AN patients, the percentage of unbound FSH was higher than in controls (P<0.05), and decreased after GnRH administration (P<0.001), whereas the percentages of unbound LH were not significantly different from controls either before or after GnRH administration. These data suggest that: (a) the acute administration of GnRH induces quantitative and qualitative changes in circulating gonadotropin isoforms in both normal controls and AN patients; (b) during recovery the LH response in re-fed AN patients is associated with a glycosylation pattern that is the same as that for controls.
Savastano
S
S
Department of Molecular and Clinical Endocrinology and Oncology, University Frederico II, Naples, Italy.
Tommaselli
A P
AP
Valentino
R
R
Luciano
A
A
Gigante
M
M
Randazzo
G
G
Contaldo
F
F
Scalfi
L
L
Lombardi
G
G
D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000097:blood* / Q000188:drug therapy*; D003208:Concanavalin A / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood* / Q000378:metabolism; D005502:Food; D006031:Glycosylation; D007987:Gonadotropin-Releasing Hormone / Q000627:therapeutic use*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood* / Q000378:metabolism; D012016:Reference Values; D013997:Time Factors
D003208:Concanavalin A; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone